#include <iostream>
#include <algorithm>
using namespace std;

#include <assert.h>
#include <string.h>
namespace bit
{
	class string
	{
	public:
		typedef char* iterator;
		iterator begin()
		{
			return _str;
		}

		iterator end()
		{
			return _str + _size;
		}

		string(const char* str = "")
			:_size(strlen(str))
			, _capacity(_size)
		{
			//cout << "string(char* str) -- 构造" << endl;

			_str = new char[_capacity + 1];
			strcpy(_str, str);
		}

		// s1.swap(s2)
		void swap(string& s)
		{
			::swap(_str, s._str);
			::swap(_size, s._size);
			::swap(_capacity, s._capacity);
		}

		// 拷贝构造
		string(const string& s)
		{
			cout << "string(const string& s) -- 深拷贝" << endl;

			string tmp(s._str);
			swap(tmp);
		}

		// 移动构造
		string(string&& s)
		{
			cout << "string(string&& s) -- 移动拷贝" << endl;

			swap(s);
		}

		// 赋值重载
		string& operator=(const string& s)
		{
			cout << "string& operator=(const string& s) -- 深拷贝" << endl;
			/*string tmp(s);
			swap(tmp);*/
			if (this != &s)
			{
				char* tmp = new char[s._capacity+1];
				strcpy(tmp, s._str);

				delete[] _str;
				_str = tmp;
				_size = s._size;
				_capacity = s._capacity;
			}

			return *this;
		}

		// 移动赋值
		string& operator=(string&& s)
		{
			cout << "string& operator=(string&& s)-- 移动赋值" << endl;

			swap(s);
			return *this;
		}

		~string()
		{
			delete[] _str;
			_str = nullptr;
		}

		char& operator[](size_t pos)
		{
			assert(pos < _size);
			return _str[pos];
		}

		void reserve(size_t n)
		{
			if (n > _capacity)
			{
				char* tmp = new char[n + 1];
				strcpy(tmp, _str);
				delete[] _str;
				_str = tmp;

				_capacity = n;
			}
		}

		void push_back(char ch)
		{
			if (_size >= _capacity)
			{
				size_t newcapacity = _capacity == 0 ? 4 : _capacity * 2;
				reserve(newcapacity);
			}

			_str[_size] = ch;
			++_size;
			_str[_size] = '\0';
		}

		//string operator+=(char ch)
		string& operator+=(char ch)
		{
			push_back(ch);
			return *this;
		}

		const char* c_str() const
		{
			return _str;
		}
	private:
		char* _str = nullptr;
		size_t _size = 0;
		size_t _capacity = 0; // 不包含最后做标识的\0
	};

	bit::string to_string(int x)
	{
		bit::string ret;
		while (x)
		{
			int val = x % 10;
			x /= 10;
			ret += ('0' + val);
		}

		reverse(ret.begin(), ret.end());

		return ret;
	}
}

int main()
{
	bit::string s;
    s = bit::to_string(1234);
	// bit::string s1("hello world");
	// bit::string s2 = s1;
	// bit::string s3 = move(s1);

	return 0;
}